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Mailchimp Sync

This extension keeps Mailchimp Audience(s) in sync with CiviCRM mailing groups.

Overview of features

  • Keep your Mailchimp Audiences/Lists in sync with CiviCRM groups:

    • Being subscribed at Mailchimp means being added to the group in CiviCRM; being unsubscribed at Mailchimp means being removed from the group in CiviCRM.

    • Two-way sync: subscription or group changes can be made at either end.

    • Suitable for big lists (e.g. has run happily with 250,000 contacts) thanks to an incremental sync routine that checks for recent changes rather than syncing the whole list.

  • Link Mailchimp "Interests" with CiviCRM groups.

    • It's cheaper in Mailchimp to have one audience and to segment by using "Interest groups" and "Interests". This extension allows you to link these interest groups with CiviCRM groups.

    • Two-way sync: changes can be made at either end.

  • Pump other data up to Mailchimp so you can segment or include content in merge tags.

    • You could send data like Membership end date, date of last donation, postal address.

    • You can develop your own extensions to feed Mailchimp with other information from CiviCRM using sync hooks.

    • One-way sync: changes made at Mailchimp will never migrate into CiviCRM and will be overwritten.

  • Supports multiple Mailchimp Accounts.

Health warning

While these goals sound simple, both services (Mailchimp and CiviCRM) work in quite different ways and there can be a lot of data. These facts make the process difficult and give birth to a host of complex situations that can prevent things being in sync.

Certain decisions have been made, based on a fair bit of experience, to make things as efficient and reliable as possible, but there are still limitations.

If you can, don't use Mailchimp!

In working with the API and the documentation over the last 8 years or so I've found several bugs, reported them, had them acknowledged with a promise of passing it on, yet nothing happens. They've also changed things without publishing the changes. Mailchimp's API Reference does not give a complete picture of the service. All this makes integration extensions brittle. See Mailchimp issues

Seems the customers have not found a way to apply enough pressure collectively to improve their product. Humph.

All this is a good reason to persuade people not to use Mailchimp at all if feasible. CiviCRM + Mosaico gives a descent experience for 80% of use cases and gives you more segmentation flexibility and usually much lower cost.

Why not one of the other Mailchimp extensions?

Read the reasons for writing a new extension.

How do I get started?

You backup CiviCRM and Mailchimp, then see How to Install (hint: like any other extension), then head over to the tutorial.